The late stage of AIDS generally refers to the final stage after HIV infection, which is the AIDS phase. During this period, patients may exhibit many symptoms due to various secondary infections, such as fever, night sweats, diarrhea lasting for more than one month, and weight loss of more than 10%; some patients may develop neuropsychiatric symptoms, such as headache, epilepsy, and dementia. In addition, there may be persistent generalized lymph node enlargement and various opportunistic infections, such as Pneumocystis carinii infection, chronic cough, decreased blood oxygen, and pulmonary rales. There can also be digestive system infections, such as fungal esophagitis, and cranial infections, such as viral meningoencephalitis. These secondary infections and tumors can eventually lead to death.